Plasma re-distribution in the African low-latitude ionosphere during intense geomagnetic storms

S O Ikubanni S O Ikubanni,B O Adebesin B O Adebesin,O S Bolaji O S Bolaji,J O Adeniyi J O Adeniyi,B W Joshua B W Joshua,S J Adebiyi S J Adebiyi,B J Adekoya B J Adekoya

doi:10.46481/jnsps.2020.112

Abstract

Intense geomagnetic storms offer opportunity to understand ionospheric response to space weather events. Using Total Electron Content (TEC) data from stations along the east African sector, the two most intense storms during the 24th solar cycle, with similarly occurrence season and time were studied. We observe that ionospheric effect during the main phase is not a function of the severity of the storm, whereas the more intense storm shows greater influence on the African ionosphere during the recovery phase. Plasma movement within the equatorial ionization anomaly (EIA) was evident particularly during the recovery phase, especially during the 2015 event. For both storms, the nighttime/early morning ionospheric effect is more pronounced than the daytime effects across all stations. 

Highlights

Intense geomagnetic storms offer opportunity to understand ionospheric response to space weather events
We limit the review to published observations ion before the storm to between 80 – 90 % during the 2015 of ionospheric responses in the low latitude/equatorial regions. storm; and attributed the sudden increase in O+ to the effect of Hairston et al [6] analysis of plasma flows, densities, compo- disturbance neutral winds on the post-midnight equatorial ionosition, and temperatures obtained from five polar-orbiting De- sphere [14]
Total Electron Content (TEC) was obtained from the Receiver Independent Exchange (RINEX) and CODE files by applying a procedure developed at the Boston College and package in the software “Global Positioning System (GPS) v2.9.5”, which is freely available at “http://seemala.blogspot.com/”.Using some stations within the African equatorial ionization anomaly (EIA), we investigated the TEC magnitude at both crests of the EIA in relation to the trough, the asymmetry at the two crests and fountain plasma reversal during the storm main and recovery phases

Summary

Introduction depends on the driving conditions and ionospheric conductivity

Energetic mass particles released during solar storms impact the Earth’s magnetosphere if earth-directed. Observations of the geospace effects of the St. Patrick’s disturbed electric fields, which are the PPEF and DDEF, were Day storms over the African sector are very limited; some of decisive during both storms. Single-frequency Global Navigation Satellite Systems (GNSS) documented observations of equatorial ionospheric irregularicaused by ionospheric delays due to deviation from the quiet- ties across several sectors, the African sector inclusive, using time total electron content (TEC) average can be large, leading the Rate of Change of TEC index (ROTI) as indicator. The limitation of [4], based on this, is that the southat the East Pacific and the Indian sectors due to the time of the ern stations employed all fall beyond the EIA crest For this southward turning of IMF-Bz. The DDEF, usually long-lived, is a product of the enhanced 5 oS of the geographical equator have been employed. Pub/rinex/obs/).Satellite and receiver biases contained in files from Center for Orbit Determination in Europe (CODE) and available at “ftp://ftp.unibe.ch/aiub/CODE” was retrieved

Results and Discussion

Description of the storms

Conclusion